What types of indexes are available in PostgreSQL?

In PostgreSQL, there are several types of indexes, each optimized for different tasks:

• B-tree (default) — suitable for most comparison operations (=, <, <=, >, >=), used for both unique and non-unique indexes.
• Hash — efficient for equality operations (=), but less versatile and used less frequently.
• GiST (Generalized Search Tree) — supports complex data structures, such as geometric objects, full-text search.
• SP-GiST (Space-partitioned GiST) — for specific data structures with space partitioning, such as points, networks.
• GIN (Generalized Inverted Index) — optimal for indexing arrays, JSONB, full-text search.
• BRIN (Block Range Index) — a compact index for very large tables with ordered data, indexes block ranges.

The choice of index type depends on the nature of the data and queries. For example, GIN is used for full-text search, GiST for geometric data, and B-tree for regular comparisons.